Crankless mechanism



Sept. 17,1935. HERMA 2,014,702

CRANKLESS MECHANI SM Filed Aug. '7, 1934 IVNVENTOR Thomas LS/Irmcm I JQIMLPH ATTORNEYS Patented Sept. 17, 1935 UNITED STATES PATENT OFFICE CRANKLESS MECHANISM Thomas L. Sherman, New York, N. Y., assignor to Michell-Crankless Engines Corporation, New York, N. Y., a corporation of New York This invention. relates to crankless mechanisms and particularly to means for guiding the reciprocating units or pistons during their reciprocation, and for preventing any rotational movement thereof.

In crankless mechanisms, such as crankless engines, the power is transmitted from the pistons to the shaft by means of bearing members or slipper pads carried by the reciprocating unit or piston and engaging a slant or swash plate mounted on the shaft. The normal type of reciprocating unit used in such engines is simply illustrated in Fig. 1 of applicants United States Patent No. 1,897,771 in which the reciprocating unit is supported or guided by bearings concentrio with the axis of the cylinder and located in the end walls of the slant chamber at both sides of the slant.

In engines of the single ended type in which the reciprocating unit has a piston on one side only of the slant, the extension of the reciprocating unit to the outer guide bearing necessitates lengthening of the mechanism and its casing in order to accommodate the stroke movement of the extension of the unit. This extension serves no other. useful purpose. Furthermore, it increases the weight of the reciprocating unit and so is undesirable for high speed engines.

This invention applies particularly to engines of the single ended type and has for its salient object the elimination of unnecessary material and weight in the reciprocating piston unit, the avoidance of the guiding extension and further to provide a construction that will efficiently guide the unit Without requiring great accuracy or precision in manufacture.

Another object of the invention is to so locate the guide means or bushings for the reciprocating unit of crankless mechanism that the forces tending to load the piston skirt will be in substantial equilibrium or will be reduced to a negligible order.

Further objects of the invention will appear 45 from the following specification taken in connection with the drawing which forms a part of this application, and in which Fig. 1 is a longitudinal sectional elevation of a portion of acrankless mechanism showing guide 5 means constructed in accordance with the invention;

Fig. 2 is a transverse sectional elevation through the guiding means;

Fig. 3 is a detail sectional elevation of the guide 55 rods or bars;

Fig. 4 is a longitudinal elevational view of one of the bars or rods shown in Fig. 3;

Fig. 5 is a sectional elevation illustrating a slightly modified form of guiding means;

Fig. 6 is an enlarged sectional elevation of the 5 reciprocating unit and guiding means showing the bushes so located as to minimize or neutralize forces tending to load the piston bearing or skirt; and

Fig. 7 is a diagrammatic View illustrating the 10 forces acting on the slipperpad of a crankless engine.

The invention has been Worked out to accomplish two interrelated functions, namely, to provide guiding means for maintaining the recipro- 15 eating unit in a true path of reciprocation during its movement, by so designing and locating the guide bushes that forces or turning moments tending to load the piston bearing or skirt will be minimized or neutralized, and further to de- 20 sign the guiding means so as to effectively accomplish its purpose without requiring great accuracy or precision in manufacture and also to provide against restraints arising from thermal conditions.

The first object is accomplished by providing two bushes which are carried by the reciprocating unit and are guided during the reciprocation of the unit on stationary guiding rods, the bushes being so located with respect to the slipper pad 30 nearest the piston that the side loading carried by the piston skirt is reduced to a minimum.

The other object is accomplished by so locating the guiding rods in the engine casing that they can automatically adjust themselves to pro- 3 vide against manufacturing errors and other irregularities.

Further details of the invention will appear from the following description.

In the particular embodiment of the invention illustrated in the drawing there is shown a portion of a crankless engine casing it) having a cylinder H and a shaft l2 upon which is mounted a slant 4%. The cylinder axis and axis of reciprocation of the piston is shown at A-A.

.A piston P is mounted in the cylinder and comprises a head M and a skirt iii. The outer end of the piston has mounted therein a socket it in which is pivoted a slipper pad bearing H. The slipper pad I7 is provided with the usual plane bearing surface 18 which is disposed in engagement with the slant l3.

The crankless engine illustrated is of the single-ended type and the reciprocating unit is provided with guiding means to maintain the unit in a true path of reciprocation during its operation. This guiding means comprises a bridge member 20 having depending portions at the ends thereof, the socket l6 being mounted in the depending portion at one side of the slant and a socket 2| being mounted in the depending portion at the other side of the slant. A slipper pad 22 is pivotally mounted in the socket 2i and engages the opposite face of the slant I3, from that engaged by the slipper pad 11. The bridge member 20 carries a pair of bushes 25 and 25 which are slidably mounted on guide rods 21 and 28. The rods are mounted in any suitable manner on the engine casing. One of the rods, such as the rod 21 is fixedly mounted but the other rod 28 is so mounted as to permit a limited swinging movement toward or away from the rod 21. In the form of the invention shown in Figs. 3 and 4, the rod 28 is shown as provided at its ends with eccentric bearing portions 29 and 30 which are rotatably mounted in suitable bearing brackets or other means provided in the engine casing. From the showing particularly in Fig. 3 it will be seen that the rod 28 is permitted by this eccentric mounting, a limited lateral movement toward or away from the rod 21. The bearing portions 29 and 30 of the rod 28, as stated, are mounted in suitable bearings and are freely rotatable so as to permit the rod 23 to accommodate itself to the location of the bushing which reciprocates thereon. Because of this construction any slight inaccuracy in variation in the relative locations of the bushings 25 and 26 in the bridge portion will be taken care of and undue precision in manufacture is unnecessary.

Thus, the dimension M in Fig. 3 may vary within limits without interfering with the proper guiding of the reciprocating unit. It will be realized that for the order of the inaccuracies or variations involved the small movement at right angles, as the result of movement on an arc, can be regarded as having a negligible efiect on the position of the slipper pad with respect to the axis A-A.

This same result may be accomplished in the manner shown in Fig. 5 by providing a square opening 35 in the bridge member 20A and providing a square bushing 36 of slightly smaller width than the width of the opening 35. The bushing 36 is slidably mounted on one of the guide rods 31. With this construction the limited lateral movement of the square bushing or block 36 takes care of any slight inaccuracies or variations in the dimension M and so permits both guide rods to be fixedly located.

In Fig. 7 there are shown diagrammatically the forces acting between the slipper pad and slant. The load imposed on or transferred to the slipper pad is shown at P, O. This load is either coaxial with or parallel to the axis of reciprocation of the reciprocating unit. The slipper-slant force acts in the direction 0, Q and neglecting friction can be regarded as normal to the slant surface. The resultant reaction to secure equilibrium is P, Q. This reaction must be in the plane X, X, i. e. in the plane of the center of the spherical mounting of the slipper pad. If these were the only forces acting on the reciprocating unit then the correct position of the guide bushes would be in the plane X, X (see also .Fig. and there would be no lateral loading on the piston skirt 40 necessary for equilibrium.

The mass of the reciprocating unit, however,

is not symmetrically disposed about the axis AA and so the theoretical conditions described above do not exist in an actual machine. Due to the offset mass of metal to carry the guide bushes and to a portion of the bridge itself just beyond 5 the slant the center of gravity of the reciprocating unit will be approximately, as shown at I in Fig. 6, at a distance Y from the axis A-A. The rotational effect of this inertia on the reciprocating unit at the in-dead center position of the 10 piston would tend to cause rotation in the direction S and consequent loading on the piston skirt.

By arranging that the plane of the guide bushes shall be at a distance A from the slipper pad center mounting the skirt loading can be neu- 15 tralized or minimized as desired. For example, at the in-dead center position, the reaction P, Q (Fig. 8) acts in a direction radially inwards towards the main shaft I2, and so tends to produce a rotation T about the guide bush opposite 0 to the rotation S above. Consideration of the conditions existing at the out-dead center position shows a similar advantage in securing equilibrium. In any given machine the magni. tude of the dimension A would be chosen to 25 give the lowest average loading on the piston skirt.

From the foregoing specification it will be clear that guiding means for guiding the reciprocating unit of a crankless engine has been so designed 30 as to effectively accomplish the purpose without requiring undue precision or accuracy in manufacture and furthermore it will be clear that the location of the guide bushes in the manner explained will effectively overcome and neutralize 35 turning moments tending to place a lateral loading on the piston skirt.

Although certain specific embodiments of the invention have been particularly shown and described it will be understood that the invention 40 is capable of modification and that changes in the construction and in the arrangement of the various cooperating parts may be made without departing from the spirit or scope of the invention, as expressed in the following claims.

What I claim is:

1. In crankless mechanism, a cylinder, a piston reciprocatable therein, a shaft, a slant mounted thereon, a slipper coacting with the piston and slant to transmit motion therebetween, a bridge member carried by the piston having bushings therein and guiderods for said bushings, one rod being adjustable toward and away from the other rod, said bridge member having a bearing for the slipper located between said guide rods and nearer the slant shaft than said rods.

2. In crankless mechanism, a cylinder, a piston reciprocatable therein, a shaft, a slant mounted thereon, a slipper coacting with the piston and slant to transmit motion therebetween, a bridge member carried by the piston having bushings therein and guide rods for said bushings, one rod being supported for free movement toward and away from the other, said bridge member having a bearing for the slipper located between said guide rods and nearer the slant shaft than said rods.

3. In crankless mechanism, a cylinder, a piston reciprocatable therein, a shaft, a slant mounted thereon, a slipper coacting with the piston and slant to transmit motion therebetween, a bridge member carried by the piston having bushings therein and guide rods for said bushings, one rod being eccentrically supported for movement relative to the other rod, said bridge member having a bearing for the slipper located between said guide rods and nearer the slant shaft than said rods.

4. In crankless mechanism, a cylinder, a piston reciprocatable therein, a shaft, a slant mounted thereon, a slipper coacting with the piston and slant to transmit motion therebetween, a pair of guide rods, one rod being mounted for movement relative to the other, and bushes connected to the piston and mounted on said rods, said bridge member having a bearing for the slipper located substantially equidistant from said guide rods.

5. In crankless mechanism, a cylinder, a. piston reciprocatable therein, a shaft, a slant mounted thereon, a slipper coacting with the piston and slant to transmit motion therebetween, a pair of guide rods, one rod being mounted on eccentric supports for movement relative to the other, and bushes connected to the piston and mounted on said rods, said bridge member having a. bearing for the slipper located substantially equidistant from said guide rods.

6. In crankless mechanism, a cylinder, a reciprocatable unit mounted therein, a shaft, a slant mounted thereon, a slipper pad pivoted on said unit and engaging the slant, a pair of guide rods, and bushes carried by the unit and mounted on said rods, a plane including the vertical center lines through the bushes being disposed approximately in a vertical plane including the pivot of the slipper pad.

'7. In crankless mechanism, a cylinder, 2, reciprocatable umt mounted therein, a shaft, a slant mounted thereon, a slipper pad pivoted on the unit and engaging the slant, guide rods, and bushes mounted on the rods and carried by the reciprocatable unit the center of gravity of. the bushes and the pivot of the slipper pad being disposed in a common vertical plane.

8. In crankless mechanism, a cylinder, a reciprocatable unit including a piston mounted therein, a shaft, a slant mounted thereon, a slipper pad pivoted on said unit and engaging the slant, a pair of guide rods, and bushes carried by the unit and mounted on said rods, a plane including the vertical center lines through the bushes being disposed approximately in a vertical plane including the pivot of the slipper pad, said piston having a land adjacent the piston head engaging the cylinder wall.

9. In crankless mechanism, a cylinder, a reciprocatable unit mounted therein, a shaft, a slant mounted thereon, a slipper pad pivoted on said unit and engaging the slant, a pair of guide rods, and bushes carried by the unit and mounted on said rods, a plane including the vertical center lines through the bushes being disposed between the pivot of the slipper pad and the reciprocating unit.

10. In crankless mechanism, a cylinder, a reciprocatable unit mounted therein, a shaft, a slant mounted thereon, a slipper pad pivoted on said unit and engaging the slant, a pair of guide rods, and bushes carried by the unit and mounted on said rods, a vertical plane through the bushes mid-way between the ends thereof being disposed between the slipper pad and the reciprocating unit.

11. In crankless mechanism, a cylinder, a reciprocatable piston mounted therein, a shaft, a slant mounted thereon, a slipper pad pivoted on said piston and engaging the slant, a pair of guide rods, and bushes carried by the piston and mounted on said rods, a vertical plane through the center of gravity of the bushes being disposed between the pivot of the slipper pad and the reciprocating piston.

12. In crankless mechanism, a cylinder, a piston reciprocatable therein, a shaft, a slant mounted thereon, a slipper coacting with the piston and slant to transmit motion therebetween, a bridge member carried by the piston having bushings therein and guide rods for said bushings, one rod being supported in bearing members slidably mounted relative to the other rod, said bridge member having a bearing for the slipper located between said guide rods and nearer the slant shaft than said rods.

THOMAS L. SHERMAN. 

